This is a 1974 Chevy 350, a 3970010 casting, number K01-27-CMJ that tells me it came in a police car with a 4BBL carb and TH400 automatic. I have the TH400 that it came with. The existing heads are casting 333882 which have a 76 cc volume. I'm in the cam and head selection process and would like it to be no lower than a 9.0 CR. I'm looking for aluminum heads in the 64 cc range and a flat-tappet cam, something like an L79. ATTACH]3000364[/ATTACH] So if anyone could tell me what these pistons are, I would appreciate it. The dish is about .080 deep.
You should be about 8:1 with that one, a closed chamber head should net you somewhere in the neighborhood of 9-9.5:1
I'm in the same exact boat on this one. I've got a 72 350 block and intend to put 64cc chambered 462 iron heads on it. I have also been told numerous times that I should see close to 9.5 to 1 for compression.
Most 4 valve relief pistons are cut the same, so I'd measure how far the piston is in the hole at TDC, then start plugging numbers into a CR calculator to see what you can come up with via compressed head gaskets thickness, stroke and CC size you want to use.
From my experience most that I have built have been. .020 in the hole.. I usually use a .018 steel shim head gasket to get a .038 quench an about 9.5 to 1 with a 64. cc head...
Thanks all. I'll plug and chug some numbers into a CR calculator and see what comes up for gasket options. I was hoping not to have to change pistons right now and the motor itself is low miles and clean inside. It will come apart for a look-see, new oil pump, rear main & gaskets.
The Jalopy Journal
